This invention relates generally to the field of sterilizing and destroying the hypodermic needle component of the syringe so as to render it safe for disposal. More particularly, this invention relates to a self-contained apparatus, having an improved electrode structure, which melts or vaporizes and sterilizes the hypodermic needle component of a syringe by passing electricity continuously along portions of the needle component until significantly all of the needle portion has been burned due to heat produced by the electrical resistance through the needle component.
Current medical practice favors one-time use hypodermic needle syringes over reusable syringes. After a one-time use hypodermic needle syringe has been used, it must be disposed of properly. A used hypodermic needle syringe often poses a health hazard to any person coming into contact with a contaminated needle or syringe. The widespread exposure of contagious and fatal diseases multiplies this danger.
The most common method for disposing of used hypodermic needle syringes is a xe2x80x9csharpsxe2x80x9d container. A sharps container merely is a plastic container into which the used hypodermic needle syringes are placed. When the container is full, a cap is placed on the container and the container is disposed of. Typically, a service picks up the full sharps containers and disposes of the full containers either through incineration or in landfills. When destroyed in incinerators, the sharps container provides a sufficient method of disposal of the used hypodermic needle syringes. However, sharps containers suffer from several disadvantages. First, the used hypodermic needle syringes are not sterilized before being placed in the sharps container. This can lead to unintentional contact with a contaminated needle. Second, if the sharps containers are disposed of in a landfill, there always is the possibility that the sharps container can inadvertently open or be broken, thus exposing the contaminated needles.
In U.S. Pat. No. 4,628,269 to Ch""ing-Lung, a device is disclosed for severing a needle from its syringe. The Ch""ing-Lung device comprises a pair of spaced apart electrodes within a self-contained unit. The needle of the syringe is inserted into an opening in the unit until the base of the needle component is positioned between the two electrodes. When electricity is passed between the electrodes, the electricity causes the portion of the needle between the electrodes to melt, thus severing the needle from the syringe body. The needle portion falls into a collection means and can be disposed. The Ch""ing Lung device does not destroy the needle, but merely severs the needle from the syringe body. Therefore, the Ch""ing-Lung device does not eliminate the dangers of contamination from the end of the needle, nor the safety hazard obvious from having many loose needle heads in the unit.
A plastic syringe destruction device is disclosed in U.S. Pat. No. 4,860,958 to Yerman. The Yerman device employs a cylinder and piston compaction unit which uses heat to thermally smash complete plastic syringes, including the needle component, into a compacted mass. One or more plastic syringes are placed in the cylinder and the cylinder lid is closed. The syringes then are heated to temperatures between 100xc2x0 C. and 200xc2x0 C. to bring about melting of the syringes, as well as sterilization. The piston travels upwardly in the cylinder while the syringes are at a desired temperature, thus compacting the softened or molten plastic syringes into the compacted mass. The Yerman device suffers from several disadvantages, the most important of which is that the syringes are not raised to a temperature high enough to destroy the metal needle portion of the syringe. After the plastic syringes have been compacted into a mass, the metal needles typically protrude from the plastic mass, thus still posing a danger to the operator. Although the needles may have been sterilized, puncture wounds caused by the needles are neither desired nor healthy.
A hypodermic syringe needle destroying and sterilizing apparatus and method is disclosed in U.S. Pat. No. 4,877,934 to Spinello. The Spinello device is aimed specifically at destroying the metal needle portion of the hypodermic syringe by using electrical resistance heating between electrodes. The hypodermic needle is placed in a carrier which contacts the upper portion of the metal needle closest to the syringe barrel. The carrier then carries the syringe over an upwardly sloping second electrode. As the needle point contacts the second electrode, electricity passes from the second electrode through the metal needle into the first electrode, thus causing resistance heating of the metal needle. In theory, the electrical resistance heating melts and destroys the metal needle. However, in practice, the electrical resistance heating generally only softens the metal needle such that as the metal needle contacts the to upwardly sloping second electrode, the metal needle bends outward. Although the Spinello device may heat the metal needle to a temperature high enough to sterilize it, typically the metal needle remains and poses the same health and safety hazard any other sharp instrument has. Further, the Spinello device comprises many moving parts which have the potential of jamming and wearing.
U.S. Pat. No. 4,969,379 to Taylor et al. discloses a device that is essentially a syringe guillotine. The syringe is inserted into a receiving hole a certain distance, and a spring-biased piston is hand actuated forcing a cutting member down on the syringe. The process is repeated until the entire syringe has been cut into smaller portions, which portions fall to the bottom of the container. Obviously, the Taylor device suffers from the disadvantage that the syringe is not sterilized and the metal needle portion, although in smaller pieces, still presents a safety hazard. After the Taylor device is full of syringe portions, it must be disposed of in much, the same manner as the sharps containers.
An electrical syringe needle destroyer is disclosed in U.S. Pat. No. 5,336,862 to Yelvington, which has overcome some of the deficiencies of the above designs. This design operates by attempting to thoroughly burn and destroy significantly all of the needle portion of the syringe by continuously passing a sufficient amount of electricity through the needle, burning and destroying portions of the needle at a time. The destroying unit has two disc shaped electrodes. Presumably, any remaining needle portion, particularly the nub of the needle closest the syringe barrel, also has been heated, through electrical resistance heating, to a sufficient temperature for a sufficient period of time to sterilize any remaining needle portion. Unlike the prior art which acted upon only the base and tip of the needle, this design attempted to act only on a small portion of the needle at a time, eliminating the need for the high amperages and voltages required by the prior art, and eliminating the problem of needles breaking between the base and tip and needles welding themselves to the electrodes as frequently occurs in the prior art devices. However, due to the design of the disc shaped electrodes, making initial contact as well as maintaining constant contact with the two electrodes was difficult.
As embodied and broadly described herein, the invention is an apparatus for destroying metal needles having a shaft, hub, and a tip, comprising a first electrode and a second electrode, the first and second electrodes spaced apart in an overlapping relationship. The first electrode is generally disc shaped and the second electrode is generally cylindrically shaped. The apparatus further has a housing for the electrodes and for a power source, and having an orifice for receiving the needle, the first electrode overlapping the orifice.
The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate an embodiment of the invention, and, together with the description, serve to explain the principles of the invention.